Inclusion Criteria:

• Documented diagnosis of HAE (Type 1 or 2). The following must be met:

  1. Documented clinical history consistent with HAE
  2. Lab findings consistent with HAE Type 1 or 2

• Experienced at least 2 HAE attacks during the Run-In period, as confirmed by an investigator based on meeting the protocol-specified definition of an HAE attack.

Exclusion Criteria:

• Any concomitant diagnosis of another form of chronic angioedema, such as acquired C1 inhibitor deficiency, HAE with normal C1-INH (also known as HAE type 3), idiopathic angioedema, or angioedema associated with urticaria.

• Use of therapies prescribed for the prevention of HAE attacks may not be used during the trial or within the below time frames prior to the Run-In Period (adult participants may be on these medications at the time of the Screening Visit, but will need to washout prior to entering the Run-In Period).

  1. Tranexamic acid, oral danazol, oral stanazolol, and oral oxandrolone within 3 days prior to Run-In
  2. Plasma-derived C1INH for LTP within 14 days prior to Run-In
  3. Berotralstat within 21 days prior to Run-In
  4. Lanadelumab within 70 days prior to Run-In
  5. Garadacimab within 90 days prior to Run-In